Replaceable fuse



May 6, 1924. 1,492,790 J. B. GLOWACKI REPLACEABLE FUSE 'Filed July l21, 1919 lzxy Iy- Patented May 6, 1924.

y 1,492,1a UNITED STATE-s PATENT OFFICE.

,y y .IorIN n. GLowAcxI, or emcaeo, ILLINoIs.

kBEPLACEAIBLI'I kFI'J'SIE.

, Application and ,my 21, 191s. serial no. $12,342.

To all whom it `may concern. f

Be it known that I, yJOHN `B. Gnowacm,

a subject of the Republicof Poland, having ticularly those employing a cartridge con-` taining a strip or wire of readily fusible metal. ,f

VHeretofore. in fuses of thisy type thereplacement of the fuse element in the cartridge has been a diicult andy .awkward operation. Further, fuse cartridges v have not hitherto readily adapted themselves for use with currents of widelydilerent values. It is an object, therefore, of thepresent invention to `provide ya` simple, inexpensive fuse vcartridge from which the `fuse element may ybev readily removed and replaced. A. further object of the invention is to provide an improved form of fuse element,

" the current carrying` capacity of @which may be varied without change inltheconstruction or Size. of the parts of the cartridge.

yOther and further important objects of this invention will be apparent from the dis` closuresk in the specification and'drawings. The invention (in a vpreferred form) is illustrated in the drawings andhereinafter more fully described. n y f On the drawings: y Figure 1J is a side elevation with parts in section ofa fuser and ksu port therefor embodying the features of vgli vention. f

Figure 2 isla ylongitudinal sation through f the fuse cartridge. n f

Figure 3 is an end view of the fuse cartridge. Figure 4 is a side view of the fuse wires and terminals. f

'Figure 5 is a section Aon the line 5--5 yof- Figure 4. Figure 6 is aside View of the fuse wires. Figure 7 is a 'side elevation' with parts in section of a further form of fuse and support therefor.

e present in- `As shown on the drawings:

The fuse vcartridge `compr1ses a tube 1 of suitable insulating material such as fibre providedat its ends with metallic caps2 and 3. One of these caps, as 2, may, if desired, be permanently connected lby punching afportion of the cap, as at fl, into `the material of the tube. The other cap 3 is arranged to slide freely on and off the tube for replacement of the fuse strip therein.k

Within the/'tube 1,v is located the fuse element comprising-a pair of terminals 5 and an `intermediate wire or wires 6 of readily fusible meta-l. y

The capacity of the fuse is determined by the total cross-section of the fuse wires so that by varying the number of wires the capacity'may be chan ed as desired. Instead `of using separate engths of fuse wire a single piece ma Abe employed which is bent backon itse f the necessary number of times, as shown in Figure 6.

Each terminal 5 is conveniently formed at one end with a recess 7 for the reception Uf the fuse wire 6,y whichis held in position thereinr by solder 8. At the other end each terminal is provided with a threaded recess 9 for engagement with a threaded pin 10. These pins are provided with washers 11 for engagement with the outer face of the cap after the ends of the pins have been passed through the apertures in the 'caps 2 andk 3 and screwed into the terminals 5. By `employing washers the size of the washer lmay be varied for different sized cartridges,although ofcourse it is obvious that instead of using a washer as illustrated a flat shoulder may be provided on the screw or the washer may be held in place by enga ement-'with the screw head.

s the pins drawr the terminals 5 outwardly in opposite direction the wires 6 are placed in tension'and at the same time the washersll on the pins are held infirm electrical contact `with the caps 2 and 3.

In lorderthat these pins may be readily rotated slots 12 are formed in their ends, as yshown in' Figure 3, for engagement with a screw driver.

'The fuse cartridge is arranged within a suitable casing. Two forms of casings are shown, one of the contact ferrule type in Figure 1, yand the other of the knife blade type in Figure7.

The ferm of construction shown in Figure 1 comprises a tube 13, preferably of insulating material such as fibre or other suitable material provided with an apertured cap 14 at one end and a ring or ferrule 15 at the other end.

The outer end of the fer-rule 15 is reduced in diameter so that a cap 16 of the same diameter as the ferrule ma have threaded engagement therewith. y this construction a shoulder 17 is formed on the ferrule which engages the end of the tube 13 and prevents it from sliding back on the tube.

This cap 16, like the cap 14, is centrally apertured for the passage of the outer end of one of the pins 10 of the cartridge. The casing is made of such length that the distance between the outer faces of the washers 11 of the cartridge is slightly greater than the distance between the inner faces of the caps 14: and 16 of the casing when the cap 16 is screwed home on the ferrule 15. With the parts so proportioned the cartridge may be firmly gripped between the caps 14 and 16 and good electrical contact made therewith.

The casing may be supported in any convenient way such as by a base 18, furnished with spring clips 19, by which current is passed through the fuse.

In Figure 7 a casing is shown having knife blades 2O and 21 arranged at the ends of a tube of insulating material 22. One of these knife blades, as 20, is riveted to a cap 23 permanently connected to the tube of insulating material 22. For this purpose lugs 24 are formed on the end of the knife bla( e for insertion through corresponding apertures in the cap 23 and in a washer 25 arranged against the inner face of the cap. These lugs are subsequently riveted or clinched to hold the knife blade 20, cap 23 and washer 25 securely together. The cap 23 may be attached to the tube 22 in any convenient way such as by rivets 26. By using a washer a double thickness of conducting material is obtained for carrying the current from the knife blades to the fuse cartridge.

The other knife blade 21 is similarly riveted to a disc 27, provided with an outwardly extending flange 28 for engagement with a corresponding inwardly directed flange 29 on a ring 30. This ring 30 is arranged for threaded engagement with the end of a ferrule 31 riveted at 32 or otherwise secured to the tube 22.

The casing is so proportioned that the distance between the outer faces of the washers 11 on the pins 10 is slightly greater than the distance between the inner faces of the washer 25. and the disc 27, when the ring 30 is screwed home on the ferrule 31, so that good electrical contact may be obtained between the washer 25, disc 27 and the ends of the cartridge. l

It will be seen that in the construction shown in Figure 1, contact is made with the caps of the cartrid e, while in Figure 7 contact is made with t e washers 11 on the pins through washers 25 and disc 27. Either method of obtaining the desired electrical contact may be employed, although where knife blades are employed the latter method is preferable as it leaves more room for the attaching lugs 24 of the blades.

The casing may be supported in any suitable way such as by a base 33 carrying at each end a pair of spring contacts 34 for engagement with the knife blades 20 and 21.

The operation is as follows:

To replace a fuse element in the fuse shown in Figure 1, the fuse is pulled out of engagement with the spring contacts 19 and the threaded cap 16 unscrewed. When this is done the fuse cartrid e can be slid out of the casing 13. Next t e pins 10 are unscrewed from the terminals 5 of the fuse element and the detachable cap 3 is pulled oil the end of the tube 1 or the caps 3 and 16 could first be taken oi and the pins then unscrewed.

The terminals 5 of fuse element and any fused pieces of the wire 6 may then be ydropped out of the tube 1 and a. new fuse element inserted in its place.

lVith the form of construction shown in Figure 7, similar procedure is followed in replacing the fuse element.

I am aware that numerous details of construction may be varied through a wide range without departing from the principles of my invention, and I therefore do not purpose limiting the patent granted otherwise than necessitated by the prior art and the annexed claims.

I claim as my invention:

1. In a fuse device, a cylindrical tube of insulating material, s. cap secured on one end of said tube, a cap slidably mounted on the other end of said tube, each of said caps having a central opening, a screw throu h each of said openings, a fuse within said tube having a threaded recess in each end into which said screws enter, the length of the insulating tube being suicient to engage the inner face of the end of the slidable cap a metallic pressure transmitting means on each screw outside the cap, whereby tightening the screws will exert pressure against the caps and will force the slidable cap against the end of the tube and place the fuse under tension, and a housin for said fuse device comprising a cylin rical tube shorter than the distance between said pressure transmitting means, caps on said last-named tube, and screw threaded means for causing said cap to press against said pressure transmitting means.

2. In a fuse cartridge, an inner casing, an outer casing, both of said casings being of insulating materiali, a fusible conductingV element within sai inner casing, metallic caps', one on each end of said inner casing, a conductive connection from said fusible element to each of said caps, threaded pins engaged throu h said metallic caps and havin threade engagement with said fusible e ment to permit tensioning of the same, metallic contacting devices, one at each end of said outer housing, 'and a cap threaded on one of said devices adapted t exert pressure to establish good electrical connections between said contacting devices and said inner casing ca s.

In testimony whereo I have hereunto 15 subscribed my name in the presence of two subscribing witnesses.

JOHN B. GLOWACKI.

Witnesses: v

CHARLES W. HILLS, Jr., EARL M. HARDINE. 

